Transmission and control mechanism



5 1944- F. A. PARSONS TRANSMISSION AND CONTROL MECHANISM Original Filed Sept. 9, 1937 5 Sheets-Sheet l 9 M a m 7 M, m l

Aug. 29, 1944. F. A. PARSONS 2,357,222

TRANSMISSION AND CONTROL MECHANISM Original Filed Sept. 9, 1937 5 Sheets-Sheet 2 R 4 o T I N E J Md W n a l J V m II 5 t y i m d 1 my n m J 11 a a w 0 a P7 m a a \w v 1 9 w 79 7 A 5 n z 2 J 7 m J 3/ n v a D u A 4 I 6 u l. m a mm N\ H 2a H a. m 1% 1 a. W. 5 o 5 u 0 e 2 n 2 1 4 p w 3 1 m m J 9 b 5 4 a a a 2 0 Z Z 0 nr 2 w 2 z Aug. 29, 1944, F. A. PARSONS TRANSMISSION'AND CONTROL MECHANISM Original Filed Sept. 9, 19s"! 5 Sheets-Sheet 3 R A? o 2 T 7 r. V 9% 7 MW M m m 6. 8 1i w a7 A "w 2 4 r U 2 1 e 5 w w ,6

- J 4 877 6 4 a m Z 7 E II a X "We v 8/0 Q 86 a \l m w Ill 7 9 f a N a I 4 7 mm 5 m N 7 F) J Aug. 29, 1944. F. A. PARSONS 2,357,222

TRANSMISSION AND CONTROL MECHANISM Original Filed Sept. 9, 1937 5 Sheets-Sheet 4 Ill;

INVENTOR ig- 2? 663W Aug, 29 1944.

F. A. PARSONS 2,357,222

TRANSMISSION AND CONTROL MECHANISM Original Filed Sept. 9, 1937 5 Sheets-Sheet 5' 19-2" W///////////,?'//'7l? ////A Patented Aug. 29, 1944 2351.222 ramsmssrou AND CONTROL MECHANISM Fred A. Parsons, Milwaukee, Wis., asslgnor to Kearney & Trecker Corporation, West Allis, Wls., a corporation of Wisconsin Original application September 9, 1937, Serial No. 162,977, now Patent No. 2,204,693, dated June 18, 1940. Divided and this application April 1, 1940, Serial No. 327,275

9 Claims.

This invention relates to transmission and control mechanism, more particularly to a transmission including a torque responsive device adapted for operation or control of supplemental or associated mechanism.

This application is a division of my copending application Serial No. 162,977, flied September 9, 1937, Patent 2,204,693, issued June 18, 1940.

A purpose of the invention is to provide a transmission including torque responsive means suitable for the control or operation of mechanism associated with or supplemental to the transmission. 7

A further purpose is to provide the torque responsive mechanism just mentioned for use with a mechanical transmission and in a form suitable for the control or operation of supplemental or associated hydraulically operated devices.

The invention consists of the construction and combination of parts as herein illustrated, described and claimed, and in such modification of the structure illustrated and described as may be the equivalent to the structure of the claims.

Throughout this specification the same reference characters have been used to indicate the same parts, and in thedrawings:

Figure 1 is a right side elevation of a milling machine in-which the invention is incorporated.

Figure 2 is a front elevation of the same machine.

Figure 3 is a partial section taken approximately along the line 3-3 of Fig. 1, and enlarged.

Figure 4 is a sectional development of transmission and other mechanism, taken approximately along line 4--4 of Fig. 3.

Figure 5 is a section of transmission and control mechanism taken approximately along line 5-5 of Fig. 2, and enlarged.

Figure 6 is a artial left side view, partly in section, of the machine of Fig. 1.

Figure 7 is a partial vertical section showing a portion of the control mechanism of Fig. 5.

Figure 8 is an enlarged sectional view of a rate change device shown in Fig. 4.

Figure 9 is a partial section taken along line 9-9 of Fig. 8. I

Figure 10 is a diagram showing the construction and operating relationship of certain of the transmission and control mechanism of the machine. It will be understood that in this diagram the various'parts are not indicated in any comparable-scale.

Figures 11, 12 are fragments of certain of the control mechanism shown in Fig. 10.

The machine of Fig. 1 is a milling machine which includes a column 20, a tool spindle 2i rotatably supported on the column, and a work support or table 22 guided for movement on a saddle 23 in a direction transverse to the axis of the spindle, the saddle being supportedfor cross movement on a knee 24 which is vertically movable onthe column. The knee, saddle and table together provide for table movement relative to spindle 2| in three mutually transverse paths.

The spindle 2i, Fig. 1, is driven from a power source such as a motor .25, through a main clutch. generally denoted by the numeral 26. The spindle transmission may be of any suitable type but in the resent machine includes rate change and reversing mechanism of the form disclosed in my copending application resulting in Patent No. 2,204,693, issued June 18, 1940, and will not, therefore, here be described in detail. Clutch 26 may be engaged by the one direction of movement of a clutch hub 26a, Fig. 10. The other direction of movement of the clutch hub engages a brake, generally denoted by the numeral 29. A gear 30 is driven whenever the motor 25 is running, and forms the initial drive gear of a table quick traverse drive train later described. 'A gear 3| clutch 26 is engaged, and forms the initial drive gear for a table feed rate train later described.

The feed and quick traverse trains iust mentioned are alternatively connectible to drive a rotatable sleeve 32, Figs. 3, 4, carried in a box or housing 23a. fixed on saddle 23. The quick traverse train includes the initial gear 30, an idler gear train 30', Fig. 1, a gear 33, a shaft 34, an extensible universal joint shaft device 35, a shaft 36, Figs. 1, 4, a sleeve 3! rotatably journaled in the housing 23a and slidably splined with shaft 36, a jaw clutch 39 which includes a shiftable member 39a, and gears 40, 4!, which drive the sleeve 32 from clutch 39 but only when the clutch 39 is engaged.

The feed train includes the initial gear 3i, an idler gear train 42, Fig. 1, a gear 43, a shaft 44, an extensible universal joint shaft device 45, a shaft 46, Figs. 1, 4, a sleeve 41, Figs. 4, 8, rotatably joumaled in the housing 23a and slidably splined with shaft 46, a stepless feed rate changer generally denoted by the numeral 48, a torque measuring device generally denoted by the numeral 49, gears 50, 5i and an overrunning clutch device generally denoted by the numeral is driven only when 82, which may drive the sleeve 92 at a feed rate which is variable according to the adjustment of rate changer 48, but which drives only when the clutch 99 of the quick traverse train is disengaged.

The overrunning clutch 82,.Fig. 4, may be of any suitable type, but in this instance is of a well known form which includes an inner member 5211 fixed on the sleeve 92, an outer member 92b fixed on or integrally formed with the gear BI, and clutch rollers such as 82c, the inner member having cam surfaces whereby springs, not shown, may operate against he rollers to wedge the rollers for the outer member to drive the inner member except when the inner member is driven at a faster rate than the outer member and in the same direction, as occurs when the clutch 99 of thequick traverse train is engaged. By this arrangement the sleeve 32 is alternatively driven at quick traverse rate or at feed rate accordingly as the clutch 89 is engaged or disengaged, the direction of rotation being the same in either case.

The table 22 may be driven in either direction from the sleeve 92 through a table reverser generally denoted by the numeral 54, Fig. 4, which includes friction clutches 54a, 8417 each comprising a set of clutch plates in which the alternate plates are keyed with sleeve 92 and with the extended and enlarged hubs of associated bevel gears 51, 58, whereby an intermediate bevel gear 59 may be driven in opposite directions accordingly as clutch spools 54c, 94d are unitarilyaxially shifted, by means later described, in the one or the other direction, the clutch spools having an intermediate position in which neither clutch is engaged. Bevel gear 59 is connected to drive a table screw 90, Fig. 3, through a shaft ii and a bevel gear pair 92, 99, the screw 60 being slidably splined in the bore of gear 63 and engaging a nut 64 fixed in saddle 29. The screw 60 is squared at 90a for application of a crank, not shown, for manual adjustment of the table in either direction.

Either the saddle 23 or knee 24 may be driven in either direction from sleeve 92, Fig. 4, through a shaft 96, Figs. 4, 5, gears 91, 98, a reverser generally denoted by the numeral 69, a shaft 10, a gear II fixed on shaft I0, and gears I2, I9 respectively associated with a knee selector clutch I4 and a saddle selector clutch I5, the selector clutches providing -shiftable elements 14a, a, Figs. 5, 7, interlocked by a shifter lever It in such manner that engagement of the one clutch disengages the other. Reverser 89 includes a gear 11 driven from gear 88 through a gear I9, and a gear I9 driven from gear I8, in a direction opposite to gear 11, through a unitary pair of gears I9, 80, the inner hubs of the gears 11, I9 providing suitable clutch teeth in the usual manner, which can be alternatively engaged by complementary clutch teeth on the opposite ends of a shiftable clutch spool 9|, which is slidably splined on a sleeve 82 fixed on the shaft I0, the spool 8i having an intermediate position disengaged from the clutch teeth of both gears 11, 19 whereby to interrupt the power train. The saddle selector clutch member 15a is slidably splined on a saddle feed screw 99 which engages a nut 84 fixed on the housing 23a for saddle cross movement. Knee selector clutch member 14a is slidably splined on a shaft 85 which drives a knee screw 86 through bevel gears 81. 88. The feed rate changer unit 48, Figs. 4, 8, is similar to the rate changer disclosed in a copend- 29, 1935, now Patent No. 2,240,148, issued April 29, 1941, and will therefore here be only briefiy described. The rate changer includes a driving gear 9| fixed on the sleeve 41, a driven gear 92 fixed on another sleeve 99 which is rotatably mounted on sleeve 41, and gears such as 94 fixed on shafts such as 99, there being several of the gears 94 and shafts 90, preferably three, equiangularly spaced and each simultaneously engaging the driving gear 9I and driven gear 92.

.The shafts 99 are each joumaled in a cage genthe opposite ends of shafts 95, the bearings in ing application Serial No. 52,095, filed No mbf this instance being anti-friction bearings such as 91, 99. 1

Fixed for rotation or integral with each of shafts 99, Fig. 8, are conically tapered friction rolls such as 99, the axis of the shafts 99 being angularly disposed with respect to the axis of drive sleeve 41, at such angle that the outer periphery of each of the conical rolls stands parallel with the axis of the drive sleeve. Frictionally simultaneously engaging the peripheries of each of the rolls 99 there is a non-rotatable.

is prevented from rotation and carried by frame l0l in a manner permitting of a certain amount of adjustment relative to the frame whereby to simultaneously eng se the periphery of each of the friction rolls 99 with equal pressure and at corresponding roll diameters, but since the details of the ring mounting do not concern the present invention they will not here be described.

The friction contact between the rolls 99, Fig. 8, and ring I00 forces each roll and its companion gear 94 to revolve whenever cage 98 is revolved, and at a gear speed determined in part by the diameter of rolls 99 at the point of ring contact. As the ring I00 is axially shifted it contacts rolls 99 at points of differing roll diameter and changes the relative speed of the gears. Thus as the ring is adjusted to engage the smaller diameter of the rolls 99 the speed of the rolls and of the gears 94 increases, and vice versa, and the relationship of the various parts of the rate change device 48 is such that when sleeve 41 is driven at a constant speed the adjustment of ring I00 will enforce a variable speed on driven gear 92. With the parts proportioned as shown in Fig. 8 the speed of driven gear 92 may be any of a stepless series of speeds having a range from zero speed, obtained when ring I00 is engaging a small diameter of rolls 99, to a maximum speed which is somewhat less than the speed of drive shaft 49, depending on the ratio of the driving'and driven gears 9|, 92, the ratio of the smallest and largest diameters of rolls 99, etc.

Means, including the toque measuring device 49, Figs. 4, 10, are provided to automatically regulate the friction pressure between the rolls 99 and ring I00 of the rate'changer 49, as follows: The torque measuring device 49 includes relative- 1y rotatable piston and cylinder members 490,

gear 88. 'l luid is continuously supplied to the piston 490' from a positive acting pump I08, of any suitable form. drivenirom the continuously running quick traverse train sleeve 81, as by gears I08, I01, the fluid being carried from the output port "In of the pump through a channel I08, a stationary coupling member I09, a rotary coupling member IIO, an annular groove Illa, and drilled channels III, H2, in a manner to continuously urge relative rotation of piston and cylinder members 49a, 49b in the direction opposite to that urged by the transmission load carried by the gear 80. Fluid from pump I08 can escape only after the fluid pressure on piston member 490. has rotated the piston member against the resistance of the transmission load sufficiently for exposure of a drain channel N8, the fluid pressure in channel I08 therefore being at all times directly proportional to the torque load on gear 80. To provide a predetermined minimum fluid pressure in the channel I08, for reasons later explained, the piston .member 49a of the'torque measuring device 49 is continuously urged, in a direction to cover the outlet port H3, by the means of a plunger 490, the desired minimum fluid pressure being determined by the pressure of a plunger spring 49d, which is adjustable by the means of a spring abutment screw 49e. In addition to other uses, later explained, the device 49 operates as a hydraulic cushioning and shock absorbing device in the mechanical table train. A pipe channel II4, Figs. 8, 10, connects the variable pressure line I08 to piston devices, such as the piston device II5, respectively associated with the different friction rolls 99. Each of the piston devices II includes a piston II5a, operative against the bearings 98 to thrust the bearings, together with the shaft and associated friction roll 99 to the right in Fig. 8, in the direction to increase the friction pressure between the roll and friction ring I00, and includes a cylinder I Ilb formed in part by the bearing bore in the flange 98c and in part by a cap member II 50 flxed on the flange. The fluid supply from channel II4 to piston devices I I5 is through a stationary coupling member H6, a rotatable coupling member II1, an annular groove II1a and drilled channels H8, H9, I20.

By the described arrangement the friction pressure between rolls 99 and ring I00 of the rate -changer 48 is continuously automatically increased as the feed torque is increased, and vice ve rsa, but to insure that the friction pressure is relieved simultaneously with a reduction in fluid pressure in channels I08, I'I4 there is provided a spring I2I, Fig. 98 in the opposite direction from that urged by pistons N5, the spring operating through a fork member I22 having fork elements such as I22a, I 22b bearing against sleeves, such as I23, which abut the various bearings 91, the spring pressure being adjustable by the means of an adjustable abutment nut I24.

For the adjustment of the output speed of the rate changer 48 the ring I00 is axially shifted by mechanism as follows: A shifter fork I28, Figs. 3, 4, engages the frame lIlI and is guided on a rotatable cam shaft I21 and a rod I28. Shaft I21 is provided with a cam groove I21a which'is engaged by a pivoted follower member I29 carried by the fork I26, the cam shaft being rotatable from a hand wheel I30 fixed on a shaft I3! and connected with the cam shaft by bevel gears. I32,

8, continuously urging the rolls I88. A graduated feed dial I84 is rotatably carried on shaft III and readable against an indicator III, the dial preferably being graduated for somewhat less than one revolution thereofto correspond with the range oi speeds available from the rate changer 48, which ordinarily requires several revolutions of cam shaft I21 to effect. Reduction gearing is therefore provided between shaft I9I "and dial I84, including a pinion Iila, an internal gear I84a, and an idler Ill. The coin groove I 21a may be of varying angle, as shown,

' whereby to effect a preferred spacing 'of the graduations of dial I84 such, for example, as to provide numbered graduations at equal spacing on the dial but corresponding to the terms of a geometrical progression.

For the manual adjustment of the knee and saddle reverser 89, Fig. 5, there is provided a hand lever I31, Figs. 5, 6, fixed on a shaft I81a having also fixed thereon a lever I98 carrying a member I99 engaging a suitable annular groove in the shiftable reverser member 8|. The clutches 14, 15for alternative selection of knee or saddle movement may be manually operated by a hand lever I40, Fig. 5. which is fixed on a shaft I, Fig. '1, connected by bevel gears I42, I49 to the lever 18, which connects between the shiftable clutch members 14a, 15a. The reverser 89 may also be automatically shifted out of either engaged position by the resulting movement of saddle 23 or knee 24, as the case may be, there being exposed dog operable plungers I44, I48, Fig. 6, for operation by saddle dogs such as adjustable dogs I44a, I45a, and similar exposed plungers I46, I41 for operation by knee dog such as adjustable dogs I46a, I41a. The dog plungers I48, I41 are connected for alternative movement into thedog zone by a pinion I48, Figs. 5, 6, and connected for disengagement of reverser 69 by a shaft I49, a gear I80, and a rack bar I5I which engages the gear I50 and also engages another gear I52 fixed on the hand lever shaft l31a, The dog plungers I44, I45 are similarly connected for alternative movement into the dog zone by a pinion I59, and connected for reverser disengagement by a shaft I54 and a segment I55 engaging the rack bar I5I.

For the control of longitudinal movement of table 22 a trip post I56, Figs. 2, 10, is mounted for both oscillatory and axial movement adjacent the front longitudinal edge of the table and is shiftable to effect either such movements by a. hand lever I51 mounted for universal movement on a ball pivot I51a, the lever connecting for movement of post I56 by the means of an inner extension terminating in a spherical portion I51b which engages a suitable bore in the trip post. Associated with trip post I56 there is a table reverser and interrupter valve device generally denoted by the numeral I58, Fig. 10, and a selector valve device generally denoted by the numeral I59, Fig. 10, for alternative selection of feed or quick traverse rate.

Reverser valve I58, Fig. 10, includes a valve plunger I58a connected for endwise movement from the oscillation of trip post I56 by the means of a lever I80 fixed on the trip post, the lever engaging a slot I58b in the valve plunger. Pres- I580 of the valve, either from the pressure channel I08, in which the pressure is controlled by the torque measuring device 49 as previously described, or from a constant pressure supply source such as a pressure channel I68 supplied from a pump I89. driven from the constantly running sleeve 81, Fig. 4, by gears I18, "I, the pressurein channel I88 being controlled by an adjustable relief valve I88a of any suitable well known form, the connection of the different pressure lines I88, I88 to the inlet port I58c being through a oneway valve device I8I which includes spring pressed ball I8Ia, I8lb respectively seated to yieldably close the inlet of fluid from ports IlIc, I8 I d, whereby to prevent outlet of fluidwhile permitting inlet of fluid through either port, the ports being respectively connected with the pressure lines I88 and I88. An outlet port Ille is connected to the inlet port I58c of the reverser valve,

through a channel I8If. The valve I8I continuously supplies fluid to port I58c from whichever of the pressure lines I88, I88 is carrying the highest pressure.

The reverser valve I58, Fig. 10, controls the operation of the reverser interrupter 54, there being a revrser piston device generally denoted by the numeral I82 including a piston I82a fixed on a piston rod [82b upon which are also fixed shifter fork members I83, I84 unitarily shiftable and respectively engaging suitable annular grooves in the clutch shifter spools 54c, 54d of the different reverser clutche 54a, 54b. In the one direction of movement of reverser valve I58 the pressure port I580 supplies fluid to a port I820 of piston device I82 through an annular groove I58d, a port I58e and a channel I58ee, whereby to engage the reverser clutch 54b. In the other direction of movement of reverser valve I58 pressure fluid is similarly supplied to port I82d of the piston device through an annular groove I58], a port 158g and a channel I58gg, whereby to engage the reverser clutch 54a, The movement of valve member I58a to supply fluid pressure to one end of piston I82a, whereby to engage one reverser clutch 54a, 54b connects the other end of the piston I82a to drain through one or the other of the annular grooves I58d, I58! and drain ports I58h, I581, and in the central position of the reverser valve member I58a, which is the position shown in Fig. 10, both ends of the piston I82a are connected to the drain ports, whereby neither clutch 54a nor 54b is engaged, and movement of the table 22 will stop.

The arrangement described permits the friction clutches 54a, 54b of table reverser 54 to operate at substantially all times under only such pressure as is suillcient to prevent the friction clutches from slipping. Thus, assuming that the selector clutch 88 is in engaged position whereby the quick traverse train is driving the reverser 54 then the torque device 48 will not be driving the table and the pressure in channel I88 will be relatively small as determined by spring 48d. At such times the pressure line I88 will supplypressure fluid through valve I8I and reverser valve I58, for operation of the reverser 54, the pressure in line I88 being controlled by adjustable relief valve I88a to be suflicient to prevent clutch slip during quick traverse operation while permitting some slip at the start of the quick traverse movement to avoid shock. But if selector clutch 38 i disengaged, whereby the feed train is driving reverser 54 through torque device 48, then during any substantial cutting operations the pressure in line the relief valve. such as I88a must be at alltimes suiiiciently high for the reverser clutches to transmit the intended maximum feed torque load and .too high to permit the friction clutche 54a, 54b to act as shock absorbing devices at-the start of quick traverse. In such case the valve' "I is not required and channel I88 is connected directly to port I58c. It is also obvious that if the predetermined minimum pressure established, as previously explained, in pressure line I88 by the spring pressed plunger 480, is sufllciently high, then it will be unnecessary to operate reverser piston device I82 from pressure line I88 during quick traverse movements of the table. In such case, also, the valve I8I would be eliminated but the port I58c of the reverser valve would then be connected directly to the presure line I88.

The operation of the described control mechanism for reverser 54 is such that as the exposed hand grip portion of lever I51 is swung in one or theother direction about the vertical axis of the lever the reverser 54 is engaged to move the table 22 in the same longitudinal direction as the hand grip movement, and when the hand lever is centrally positioned the table will stop.

The selector valve I58, Fig. 10, includes a valve member I580, flxed with trip post I58 to form the lower portion thereof. The selector valve controls the operation of the selector clutch 88, Figs. 4, 10, there being a selector piston device generally denoted as I88, which includes a piston I58a fixed on a piston rod I88b upon which is also fixed a shifter fork I81 engaging a suitable annular groove in the shiftable clutch member 88a. Pressure fluid is continuously supplied to an inlet port I58b of valve I58 from any suitable pressure source, such as the pressure line I88 supplied from the pump I88. In the upward movement of post I58 and selector valve member I58a the pressure port I58b supplies fluid to a port I 880 of piston device I88 through an annular groove I580 and a port I58d, whereby to shift clutch 38 to its quick traverse position. In the downward movement of the selector valve pressure fluid is similarly supplied to a port I88d of the piston device through an annular groove I58e and a port I58f, whereby to shift clutch 88 to the disengaged position which eflfects a feed rate as previously explained. The movement of valve member I58a to supply fluid to either port of piston device I88 provides an outlet of fluid from the other end of the piston I88a through the one or the other of the annular grooves I58c, I58e and drain ports I58g or l58h.

The operation of the selector control mechanism just described is such that vertical movement of the exposed hand grip portion of lever I51, Figs. 2, 10, about its horizontal axis effects alternate feed or quick traverse rate of the transmission sleeve 32, whereby to select feed or quick traverse rate for the table, saddle, or knee, independently of the operation of the reverser control mechanism previously described.

The main clutch 28 and brake 28, Fig. 10, may be controlled independently of the table transmission reverser and selector controllers, but may also be dependently controlled in accordance with the feed or quick traverse selector whereby to automatically effect a spindle stop during quick traverse movements of the table in any of its several paths, as will now be explained.

The main clutch 28, Fig. 10, includes friction plates such as 2817, the plates being alternately slidably keyed to rotate with a clutch pulley 28c and with a drive shaft I12, which drives an initial shaft I13 of the spindle transmission through a torque measuring device generally denoted .as I14, and through a jaw coupling device I15. The torque device I14 includes relatively rotatable annular piston and cylinder members I14a, I14b which are of a construction and operation similar to the corresponding members of the torque device 49 previously described for the feed train and which therefore will not be described in detail. Both the initial feed train gear 3| and the driving jaws of the jaw coupling I15 are fixed with the cylinder member I14b, and the torque device I14 therefore measures the combined torque of the spindle train and feed transmission. Fluid is supplied to the piston of the torque device from a positive pump I16 continuously driven whenever clutch pulley 28c is running, as for instance by a gear I11 engaging with a gear 38, the fluid being supplied to the rotary piston I14a through a pressure channel I18 and a coupling device I19 similar to that used for the torque device 49. As previously explained for the device 49, the pressure in channel I18 varies according to the torque transmitted through the device. In this instance, however, since both the initial spindle drive shaft I13 and the initial feed train gear 8| are driven, through the device, the pressure in channel I18 continuously varies in accordance with the total power applied to the machine during any cutting operation.

Clutch 26 and brake 29, Fig. 10, are alternatively shifted into engagement by a piston device generally denoted as I88, which includes a piston I88a fixed on a. piston rod I88b which shifts a pivoted lever I8I by the means of a segment I8Ia engaging rack teeth I880, the lever having arms such as I8 lb engaging a shifter ring I82 by the means of suitable trunnions such as I82a, the ring engaging a suitable annular groove in the shiftable clutch hub 26a.

The piston device I88, Fig. 10, is operated by pressure fluid from the variable pressure channel I18 of the torque measuring device I14, the alternative engagement of clutch 26 or brake 28 being primarily controlled by a valve I83 having a movable valve member I83a. Fluid from the channel I18 is supplied to a valve inlet port I83b. In the one direction of movement of valve member I83a the pressure fluid may pass to a port I 88d of the piston device through an annular groove I83e, a port IBM and a control valve I84, but only in certain positions of valve I84, as later explained, whereby to engage clutch 2B. In the other direction of movement of valve member I83a the pressure fluid passes to the other port I88e of the piston device through an annular :groove I83e and a port I83f, and through the control valve I84 whereby to engage brake 29. The control valve I84 includes a movable valve member I841: which is normally urged by a spring I84b to the position shown in Fig. 10 which effects the communication as described from port I83d through port I840, annular groove I84d, and port I84e to the port IBM, and from the port I83f through port I84 annular groove I84g, and port I84h to the port l88e. When pressure fluid is admitted by valve I83 to either port of the piston device I88 the pressure in the other port is relieved through the one or the other of the annular grooves I83e or I83e and drain ports I 839, I83h.

As a result of the described arrangement the 76 main clutch and brake may be alternatively engaged by the shifting of valve I83 when valve I84 is in the normal position, but valve. I84 may be shifted out of the position described to modify the effect of valve I83 as will be later described.

The valve member I83a, Fig. 18, may be manually shifted for control of clutch 28 and brake 29 by a hand lever I85, Fig. 1, connected to the valve member I83a by the means of a shaft I88, a pinion I81, a rack bar I88, a pinion I89, a shaft I98, Figs. 1, 16, and a pinion I9I engaging suitable rack teeth in the valve member.

The clutch 28 and brake 29 may optionally be additionally controlled in accordance with the selection of feed or quick traverse table rate,,as follows: A port I84i of valve I84, Fig. 10, is connectibie to the quick traverse selecting port I58d of selector valve I58 through a control valve I82 which includes a valve member I82a manually selectively shiftable to different positions. In one position of valve member I92a the port I84i is connected to a drain port I92e through a port I92b and an annular groove I920, and in such case the operation of clutch 26 and brake 28 is only from control valve I83 and hand lever I as previously described. In the other position of valve member I82a, as shown in Fig. 10, the ports I841, I59d are connected through the port I92b, the annular groove I820 and a port I92d. In the latter case the valve member I84a will be shifted out of its spring pressed position to another position by pressure fluid from port I59d whenever selector valve I59 is shifted to quick traverse position, but will return to normal position whenever valve I59 -is in feed position, since port I8Ii is then connected through port I58d to the drain port I589. When valve I84 is shifted to said other position, if the valve I83 is then in the position ngaging brake 28, whereby clutch 28 is disengaged and spindle 2| is stationary, the spindle will remain stationary because such shifting of valve I84 merely cuts off the pressure applied to the brake through port I84h; but if valve I83 is then in the position engaging clutch 26, the shifting of valve I84 to said other position will immediately disengage clutch 26 and engage brake 28 for so long as selector valve I58 remains in quick traverse position, because in said other position of valve I84 the port I840, instead of communicating with port I88d of the piston device I88, communicates with port I88e thereof through the annular groove I84d and a port I84k, and at the same time the other port I88Id of the piston device I88 is connected to the drain port I83h through the port I846, the annular groove I84g, the port IBM and annular groove I83e.

By the means of th mechanism just described, assuming that lever I85 and valve I83 are in the position normally engaging the clutch 28, the clutch 26 and brake 29 may nevertheless be controlled to engage the brake whereby to stop the spindle and table feed train whenever selector valve I58 is shifted to quick traverse position, and to again engage the clutch to start the spindl and feed trains when selector valve I59 is next shifted to feed position. But if the lever I85 and valve I83 are in the brake engaging position the shifting of selector valve I59 will not engage the clutch.

For the automatic dog control of the reverser valve I58 and selector valve I59, mechanism is provided as follows: The exposed upper end of the trip post I56, Figs. 2, 10, is provided with oppositely extended dog operable ears or portions I56a, I 5611, Figs. 10, 11, respectively at different levels to be operated upon by dogs adjustably retained by suitable bolts in the different table slots 22a, 22b. In the intermediate position of rotation of post I56 each of the portions I56a, I56b is positioned outside the zone of dog operation, but in either of the opposite positions of oscillation of the post, which respectively adjust valve I58 to effect opposite directions of table travel as previously explained, one of the portions I56a, I56b will be swung toward th table edge into a position to be operated upon by dogs in the corresponding table slot. Suitable dogs in the one or the other table slot 22a, 22b may then operate upon the adjacent post portion I56a or I56b to raise or lower the post I56, whereby valve I59 effects changes from feed to' quick traverse rate or vice versa, as previously explained, or to swing the post on its vertical axis whereby to operate control valve I58. The construction of dogs for raising, lowering and swinging a trip post such as I58 is well understood in the art and, therefore, the dogs will not be described in detail.

Swinging the trip post I56 on its verticalaxis by the means of the table dogs may effect either of two results, namely, to stop the table movement or reversethe direction of table movement, accordingly as the post is in its feed or quick traverse position. This results from the manner of connection of the trip post to reverser valve I58 and the construction of detent mechanism generally denoted by the numeral 300, Figs. 10, 12. Detent 300 includes a spring pressed cam follower member 900a and two cam portions 300b, 3000 respectively cooperative with the follower 3000. when the trip post is in its upper or quick traverse position and in its lower or feed position, the cam portion 3001) providing a central point 300e, whereby in the upper position of post I56 the detent 300 acts to continue rotation of the trip post immediately'it has movedpast the center of its movement in either direction, and the cam portion 300:: providing a central notch 300i whereby in the lower position of post I56 the detent may retain the post in its central'table stop position. The lever I60 which connects trip post I56 to reverser valve I58 also has two portions I60a, I60b respectively engaging the slot I581) in valve member I58a when the trip post is adjusted upwardly to quick traverse position and downwardly to feed position, the lever portion I60a engaging the slot with considerable lost motion, and the lever portion I601; fitting in the slot with substantially no lost motion. By reason of the detent and lever conoperates to further rotate the post and further shift valve member I580. to effect reversal of table movement.

By the mechanism just described the table 22 can be dog controlled to effect a great variety of automatic cycles oftable movement including change from feed rate to quick traverse rate or vice versa at any point 'in either direction of table travel, and including selective stop or reversal at either or both ends of the travel, but with the limitation that the table must be traveling a quick traverse rate when automatic reversal takes place. This limitation is objectionable where the nature of the work does not permit the last portion of the forward movement before reversal to be at quick traverse rate as, for example, where it is necessary to reverse directly out of a forward cutting engagement of the work and cutter. Therefore, to effect table reversal directly from a forward feed rate to a reverse quick traverse rate, other control mechanism is provided as follows:

A pressure responsive valve I93, Fig. 10, in-

- cludes a shiftable valv member I93a, continustruction described the reverser valve I58 closely follows the rotation of the post I56 when the post is in lower or feed position and, in such case, during any dog rotation of post I56 for movement of either of the post portions I56a, I56b out of the zone of dog operation the valve member I584 then arrives at its central table stop position at a time when the cam follower 800a is engaged in the central notch 900! of the cam portion 300e, whereby the detent retains the post and valve in table stop position. But in the upper or quick traverse position of the trip post, by reason of the lost motion of the lever portion I60a, the movement of valve member I58a lags behind the post rotation whereby, in either di-- rection of post rotation, the cam follower 300a will have passed over the cam point 9 00s before the valve member arrives at table stop position, and before the table can stop the detent 300 ously urged by a spring I93b to a position where a pressure supply port I930, which is connected to pressure line I68, is blocked, and where another port I99d is connected to a drain port I99e by an annular groove I93f. A port I93p is connected to the pressure line I08 in which the pressure varies according to the feed torque load as previously explained, the connection being made through an adjustable leak valve device generally denoted by the numeral I99 for reasons later explained. At a predetermined pressure in the line I08 the fluid pressure on valve member I93a overcomes the pressure of spring I93!) and member I93a is moved to a position in which the pressure port I930 connects with the port I93d through an annular groove I93g. The pressure point in line I06 at which port I93d is connected to the pressure port I930 as described may be selectively predetermined by adjustment of a spring abutment screw I99h which has a head portion I93i providing a graduated chart I 99ii readable against a fixed indicator pointer I93k. The pointer I93k indicates on the chart the pressure point in lin I08 at which pressure fluid is supplied to port I93d, and in any desired units as, for example, in terms of pounds of feeding pressure applied to table 22.

Pressure fluid from port I93d of pressure responsive valve I99, Fig. 10, is connectible to the end portions of reverser valve member I58a, which are enclosed by the valve housing to act as pistons, whereby to effect a shifting of the valve member I58a out of either direction position thereof to theother direction position, the connection being through a valve I94 having a valve member I94a manually shiftable to determine whether the pressure controlled valve I93 shall be operative or inoperative, and through an automatic valve I95 having a valve member I95a shiftable for purposes later described. Valve member I9la has alternative positions, in one of which, for the purpose of effecting automatic table reversal, the port I93d of valve I93 is connected to a port I95b of valv I95 through a port I 96b, an annular groove I 940 and a port I9ld. In the other position of valve I94 the automatic table reverse just mentioned is not obtained, as will be later explained.

The valve member I95a, Fig. 10, is automatically shifted to opposite positions accordingly as the reverser valve I58 is in the one or the other port I95c and a port I95d, whereby the movement of reverser valve I58 to apply pressure-to reverser cylinder device I62 will also apply pressure fluid to correspondingly shift valve member I95a. The arrangement is such that, when valve I94 is adjusted to the position for effecting automatic reversalthen, in either direction position of reverser valve-I58, the valve member I95a is automatically positioned to apply pressure fluid from valve I93 to the end of valve member I 58a which will effect a shift of the valve member I58a to the other direction position. Thus, if valve member I58a is in the position in which port I58e is supplying pressure to reverser piston device I62, then valve member I950 is forced to the position in which pressure fluid from port I95b may pass to a port I58'k of valve I58 through an annular groove I95e and a port I95f although this will not occur until pressure in line I08 operates the valve I93. Similarly if valve memher 158a is in the position in which port I58y is supplying pressure fluid to reverser piston device I62, then valve member I95a is forced to the position in which pressure fluid from port I95b will pass to a port I58m of valve I58 through an annular groove I95g and a port I95h. In either instance, the result is to shift valve I58 to effect reversal but only after the pressure applied to valve I93 from pressure line I08 is in excess of the pressure predetermined by the adjustment of abutment screw I931. The construction of valve I95 is such that, when one of the ports I58k, I58m is connected to pressure fluid as described the other port is connected to one of drain ports I951 or I95k.

Reversal such as just described should not take place until pressure in line I08.rises above that required for the cutting operation, and in order to effect pressure inline I08 suflicient to operate the valve I93, and to effect table reversal at an exact selected point in the table travel, there is provided an abutment I96, Fig. 2, fixed on saddle 23, which can be contacted by a positive stop dog I9'I adjustably fixed to the rear longitudinal table edge. By the means of the mechanism described dogs such as I91 can be used to effect table reversal from a forward feed directly to a reverse quick traverse at the end of either direction of table travel, but if reversal out of a feed rate is necessary at only oneend of the table stroke the reversal or a table stop may be effected at the other of the stroke by the means of dogs operating on the trip post I56 during a forward quick traverse movement, as previously described.

The pressure fluid from port I95b, Fig. 10, which effects automatic reversal, as just described, is also used to substantially simultaneously effect a change from feed to quick traverse rate by the shifting of trip post I56 to its upper position, but it is essential that such quick traverse rate shall not become effective until after the reverser valve member I580, has been shifted past the center in its reversing movement. To effect these results the ports I58k, I58m of valve I58 are respectively connected to the ports I58lck, I58mm whereby one or the other of the latter ports receives pressure fluid at the same time as the corresponding port 558k, I58m. Another port I581 receives pressure fluid from one or the other of ports I58kk, I58mm during the reversing movement of valve member 158a, but only after the valve member I58a has been shifted-through its central position in the revers- 111g direction. The bottom end of trip post I56, which forms the valve member I590, is enclosed to act as a piston and during reversal the port I581'is'connected thereto through a valve 250 and a port l59r. 250a normally spring pressed to a position connecting' I-59r to a vent 2501) through a port 2500 and an annular groove 250d, but during the operation of reversal as just described the plunger 250a is shifted by pressure derived from port I93'd. of valve I93 through a port 250s to connect the ports I59r and I581 through the .port 2500, the annular groove 25011 and a port 250}. As soon as the table reversal is completed the valve 250 returns to the position connecting port I591 to vent 25% and the trip post I56 can then be again shifted to its feed position if desired. A screw abutment member 250g may, if desired, be adjusted to prevent the shifting of valve mem'- ber 250, and in such case reversal'will take place as described except that it will not be accompanied by a shift of post I56 to effect quick traverse rate, and the reverse movement will then start at the same rate as the forward movement.

It is sometimes desirable in the operation of the reversing means just described that, at the end of a forward feed movement, the table should be maintained stationary in the position determined by positive stop dog I9'I, Fig. 1, for a predetermined time interval before reversal into quick traverse rate. To effect this result mechanism is provided as follows: Pressure line I08, Fig. 10, which supplies the engaging pressure for reverser clutches 54a, 54b, is provided with a relief valve I98 which limits the maximum pressure applied to the clutches whereby to permit, the reverser 54 to slip while still maintaining the pressure in line I08 sufiiciently high for operation of valve I93 to effect automatic-reversal as described. The relief valve I98 may be of any suitable well known form and therefore will not be described in detail. The valve I99, which is interposed between line I08 and port I93 of valve I93, provides an adjustable restriction which includes an adjustable member I99a in threaded engagement with the casing I99b. Fluid is supplied from pressure line I08 through a port I99c, and an outlet port I99d is connected to the port I931). The threads of casing I99b fitclosely to the sides of the threads of screw I99d but in the direction from port I990 to port I99d the casing threads are enlarged to provide a spiral path at the outside of the threads-end relatively small area, through which the pressure fluid must pass. As a result of this construction fluid will be transmitted to port I931: of valve I 93 at a rate determined in part by the adjustment of relief valve I98 but mainly by the position of adjustment of member I99a, which can be adjusted to provide a preferred interval of time, following contact of positive stop dog I91 with its abutment I96, as previously described, before the valve member I93a moves sufficiently to connect the pressure line 668 for the shifting of valve I58 to effect table reversal.

The relief valve I69a, Fig. 10, which limits the pressure operating on reverser clutches 54a, 54b during quick traverse table movements, and the relief valve I98, Fig. 10, which limits the pressure on the same clutches during cutting movements, together provide overload safety devices for the transmission of table 22. The reversin The valve 250 provides a plunger 1 mechanism controlled by valve Ill may also be operated as an overload prevention device by end 88a, there is a minimum of lateral pressure.

It is to be understood that the relative position of the transmission and control mechanism may differ materially from that shown for the particular machine which has here been used to illustrate the invention. For this reason the specific location inthe machine of some of the controlsmechanism is not indicated in the drawings. In general it may be stated that the preferred position of the various control mechanism I will be such as to provide convenient access for ing the overload. To effect such result mechanism is provided whereby an overload of the table shifts reverser valve member I580 to its central position, disengaging both reverser clutches 54a, 54b whereby to stop the table until the valve is subsequently manually shifted to clutch engaging position by operation of control lever I51. The mechanism is as follows: Piston devices including pistons I58u, I581) are provided at each end of reverser valve member I58a and each having rod portions extending sufficiently to force the mem ber I58a to its central position when pressure fluid is simultaneously'applied to the pistons through ports I58w, I581. In the other man-' ually efiected position of valve I94, previously referred to, pressure fluid from port I94b, instead of effecting reversal as previously described, is simultaneously delivered to the ports I58w, I58z. through an annular groove I94e and a port I94) to effect a table stop, but only when the'table load transmitted through torque device 48 is sufflcient to raise the pressure in line I08 to a point which will operate valve I93.

During the feed rate operation of table 22, and particularly during operations generally known as climb cutting it is very desirable that there should be no lost motion between the screw 68 and nut 84 such as might result in chatter or vibration or permit the cutter to suddenly pull itself into the work at a rate faster than the selected feed rate. To eliminate such lost motion and automatically establish a force opposing axial lost motion between the screw 80 and nut 84 there is provided the following structure: Screw 60 is constructed with threads having side faces at such angle that axial pressure has relatively little tendency to initiate or resist movement of the screw laterally. A portion of the nut is cut away at one side of the nut axis, as at 64b, Fig. 3, and in the space thus provided there is a member 200 which may be acted upon by a piston device generally denoted by the numeral 2III, the piston 202 being operated by fluid pressure supplied through channels 283, 204, 285, Figs. 3, 10, from the channel I08, whereby the piston pressure varies in accordance with the feed torque load on the torque device 49 of the feed tra n. The operation of piston device 2III is to force the screw laterally to a pressure contact acting between both sides of each screw thread and the corresponding both sides of the nut threads, there being clearance at the top and bottom of the threads to permit such engagement, even after wear takes place. Where the parts are properly fitted there is very little lateral movement required and the result is to eliminate all back lash or lost motion and to establish a metal to metal pressure which will rigidly prevent lost motion movement of the screw and nut and which is automatically varied in accordance with the load to be transmitted. Moreover the pressure connection is such that during table movements at quick traverse rate, and during manual table movement from the squared screw the operator to the manually operable or manually adjustable portions of the controls, while maintaining the mutual interconnections, such as lever, shifters, forks, fluid channels, etc., of minimum length.

For the specific form of machine shown in Figs; 1 etc., all of the control devices of Fig. 10, excepting only those directly relating to the clutch 26 and brake 29, are directly housed upon or within the saddle 23 and the dependent box or housing 28a. The lower portion of the housing 28a forms a reservoir 28aa, Fig. 10, from which each of the control pressure fluid pumps I08, I11 draw fluid, and to which all fluid leakage and fluid delivered from the various drain ports of the control valves, etc., is returned by gravity. In this particular type of machine, by reason of the relative bodily movement of the control mechanism carried by saddle 23 and the control mechanism for clutch 26 and brake 28, which is carried by the column,2ll, the channel connection between port I92b of valve I92 and port I841 of valve I84 is formed in part by a flexible tube or pipe I92bb, Figs. 1, 10.

What is claimed is:

1. In a transmission and control mechanism the combination of piston and cylinder elements relatively movable to provide a variable volume chamber having an outlet vent when said elements are in a relative position for a predetermined chamber capacity, said elements being arranged in said transmission for the transmitted load to urge relative movement of the elements in a direction to reduce the volume of said chamber whereby to urge closure of said vent, and a pump connected to supply fluid to said chamber at sufficient pressure to maintain a substantially continuous flow of fluid through said vent.

2. In a transmission and control mechanism the combination of piston and cylinder elements relatively movable to provide a variable volume chamber having an outlet vent when said elements are in a relative position for a predetermined chamber capacity, said elements being arranged in said transmission for the transmitted load to urge relative movement of the elements in a direction to reduce the volume of said chamber whereby to urge closure of said vent, a pump connected to supply fluid to said chamber at; suflicient pressure to maintain a substantially continuous flow of fluid through said vent, and a pressure responsive device con-v nected for operation from said pump at a point between the pump and said vent.

3. In a transmission and control mechanism the combination of a power train including rate change means and transmission elements driven through said rate change means and arranged for the one element to drive the other, said elements providing a fluid chamber therebetween in which the fluid pressure varies in accordance with the load transmitted between the elements, and a pressure source substantially continuously connected for supplying fluid to said chamber during transmission of power through said train.

4. In a transmission and control mechanism the combination of a power train including a rate changer providing shiftable rate change elements and transmission members driven through said elements and arranged for the one member to drive the other, said members providing a fluid chamber therebetween in which the fluid pressure varies in accordance with the load transmitted between said members, a pump substantially continuously connected for supplying fluid to said chamber during transmission of power through said train, and a pressure responsive device connected for operation from said pump at a point between said pump and said chamber.

5. In a transmission and control mechanism the combination of piston and cylinder parts relatively movable to provide a variable volume pressure chamber therebetween, a driver part and a driven part, a power transmission including said parts arranged for the driver part to drive the driven part through said piston and cylinder parts in a manner for the transmitted power to urge said relative movement in a direction to reduce the volume of said pressure chamber, a pump, a pressure channel connecting said pump for fluid delivery therefrom to said chamber in any position of said relative piston and cylinder movement, and an outlet channel for receiving fluid from said chamber only after said piston and cylinder parts have been moved in the other direction to predetermined relative positions efiecting a corresponding volume of said chamber.

6. In a transmission andcontrol mechanism the combination of piston and cylinder parts relatively movable to provide a variable volume pressure chamber therebetween, a driver part and a driven part, a power transmission including. said parts arranged for the driver part to drive the driven part through said piston and cylinder parts in a manner for the transmitted power to urge said relative movement in a direction to reduce the volume of said pressure chamber, a pump, a pressure channel connecting said pump for fluid delivery therefrom to said chamber in any position of said relative piston and cylinder movement, an outlet channel for receiving fluid from said chamber only after said piston and cylinder parts have been moved in the other direction to predetermined relative positions effecting a corresponding volume of said chamber, and a pressure responsive device connected for operation from the pressure in said pressure channel.

7. In a transmission and control mechanism the combination of piston and cylinder parts relatively movable to provide a variable volume pressure chamber therebetween, a driver part including a rate change device, a driven part,

a power transmission. including said parts arrangedfor said rate change device to drive said driven part through said piston and cylinder parts in a manner for the transmitted power to urge the relative movement in a direction to reduce the volume -of said pressure chamber, a pump, a pressure channel connecting said pump for fluid delivery therefrom to said chamber in any position of said relative piston and cylinder movement, and an outlet channel for receiving fluid from said chamber only after said piston and cylinder parts have been moved in the other direction to predetermined relative positions effecting a corresponding .chamber volume.

8. In a transmission and control mechanism the combination of piston and cylinder parts relatively movable to provide a variable volume pressure chamber therebetween, a driver part including a rate change device, a driven part, a power transmission including said parts arranged for said rate change device to drive said driven part through said piston and cylinder parts in a manner for the transmitted power to urge the relative movement in a direction to reduce the volume of said pressure chamber, a pump, a pressure channel connecting said pump for fluid delivery therefrom to said chamber in any position of said relative piston and cylinder movement, an outlet channel for receiving fluid from said chamber only after said piston and cylinder parts have been moved in the other direction to predetermined relative positions effecting a corresponding chamber volume, and a pressure responsive device connected for operation from the pressure in said pressure channel.

9. In a transmission and control mechanism the combination of piston and cylinder parts relatively rotatable to provide a variable volume pressure chamber therebetween, a rotary driver part, a rotary driven part, a power transmission including said parts arranged for the driver part to rotate the driven part through said piston and cylinder parts in a manner for the transmitted torque to urge relative rotation of the piston and cylinder parts in a direction to reduce the volume of said pressure chamber, a pump, a pressure channel connecting said pump for fluid delivery therefrom to said chamber in any position of said relative piston and cylinder movement, and an outlet channel for receiving fluid from said chamber only after said piston and cylinder parts have been moved in the other direction to predetermined relative positions effecting a corresponding volume of the chamber.

FRED A. PARSONS. 

